How to bake two objects (an item and a shrink-wrapped decal on it) into one texture image?
1:UV Unwrap the sphere
2. Plug the image of the decal directly into the output of the material node.
3: Select the sphere so its active(Yellow) and drag to select the decal so it is selected(Orange)
4. In the shader editor, create an image with a resolution of say 1024x1024 or 2048x2048.
5. In the bake settings in the render properties panel, switch the bake type to emission, Check selected to Active.
6.Click Bake.
Also, you can apply this detail in texture painting by adding it as a mask in the brush settings.